> Bike helmets mitigate one of the most serious and common forms of injury while riding bikes.
A form that is still extremely rare. No-one seriously advocates helmets for car passengers, for example, even though the injury rates are very similar.
> be hit by a car
Cars don't hit people, drivers hit people.
> They don't prevent you from doing anything you would otherwise do.
They're annoying enough that they do, in practice if not in theory. To say nothing of the fact that drivers pass you closer and more dangerously if you're wearing a helmet.
> helmets are a fantastic example of reasonable PPE, not overactive safetyism.
Quite the opposite.
It's the most common sports related head injury by a wide margin and helmets are quite effective at injury reduction.[1] As a public health policy it makes a lot of sense. Anecdotally I've flown over my handlebars and hit my helmet without serious injury, and I'm sure I would have been in much worse shape otherwise.
On cars the law requires seat belts and airbags and a variety of other legally enforced safety measures. If you have a study suggesting that helmets would significantly help I'd be curious to see it.
[1] https://www.cdc.gov/mmwr/volumes/70/wr/mm7019a1.htm
Not that rare. When I was a kid (in the 90s) I lost two classmates to bike crashes. One actually dead, the other severely brain damaged for life.
Neither accident involved a car.
Both would have likely had a few broken bones at the absolute worst if they’d been wearing helmets.
I wasn’t in an especially large elementary school, either.
I'm sorry for your loss, but your school is very much an outlier; public policy should look at the overall rates, and statistically it is rare. Particularly if we're talking about an everyday school commute along surface roads (the risk profile for mountain biking or BMX-style stunt riding is quite different, and wearing helmets for those activities makes a lot of sense).